|Publication number||US4798702 A|
|Application number||US 06/906,030|
|Publication date||17 Jan 1989|
|Filing date||10 Sep 1986|
|Priority date||10 Sep 1986|
|Also published as||CA1320813C, EP0378716A1, EP0378716B1|
|Publication number||06906030, 906030, US 4798702 A, US 4798702A, US-A-4798702, US4798702 A, US4798702A|
|Inventors||Robert E. Tucker|
|Original Assignee||Tucker Robert E|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Referenced by (56), Classifications (12), Legal Events (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to a sterilizer unit and to a process for sterilizing a fluid media.
Sterilizer units making use of ultraviolet radiation are used for sterilizing fluid media such as water for consumption, use or discharge into the environment. In earlier models, the fluid media was flowed through quartz or special glass pipes which are transparent to germicidal radiation but which become clouded with residue within a short time under normal operating conditions. Since a thin film of residue greatly reduces transparency it is necessary to clean the pipes frequently. This procedure is inefficient and not practical for a continuous operation since it requires shutting down the apparatus and draining the water to reach the inner surfaces of the tubing for cleaning.
The equipment described in U. S. Pat. Nos. 3,634,025 and 3,700,406 was a great improvement over that described above but it is big, expensive and, most importantly, does not give a particularly good kill rate. The sterilizer unit described in the subject patents includes a bank of parallel ultraviolet tubes between which the fluid media is flowed along a serpentine path. It involved the discovery that pipes made of fluorinated ethylene propylene copolymer are capable of transmitting ultraviolet radiation over an extended period of time without undergoing photochemical deterioration. The non-stick properties of polytetrafluoroethylene making possible the provision of pipes which do not cloud with residue were known before but the resistance of fluorinated ethylene propylene to photochemical deterioration in a sterilizer unit was not.
In accordance with the above, it is an object of the present invention to provide an ultraviolet sterilizer unit which has the desirable features of the prior art but which is more compact, less expensive and more effective. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter.
In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated, corresponding reference numerals refer to corresponding parts and in which:
FIG. 1 is an exploded view of a sterilizer unit in accordance with the present invention;
FIG. 2 is a side elevational view in cross section of the sterilizer unit shown in FIG. 1;
FIG. 3 is a sectional view taken along line 3--3 in FIG. 2;
FIG. 4 is a sectional line taken along line 4--4 in FIG. 2;
FIG. 5 is a side elevational view in cross section of the outer section of the sterilizer unit shown in FIG. 1;
FIG. 6 is a side elevational view in cross section of the middle section;
FIG. 7 is a side elevational view in cross section of the inner section;
FIG. 8 is a side elevational view of a corrugated pipe having helical grooves;
FIG. 9 is a sectional view taken along line 9--9 in FIG. 8;
FIG. 10 is a side elevational view of a corrugated pipe having annular grooves; and,
FIG. 11 is a sectional view taken along line 11--11 in FIG. 10.
Referring to the drawings more particularly by reference character, a sterilizer unit 20 in accordance with the present invention includes a coil of corrugated pipe 22 wrapped around a germicidal radiation source 24 into the shape of a helix. In the embodiment shown, a second radiation source 26 blankets pipe 22 so that the contents of the pipe are irradiated by a radiation source from the inside and the outside of the coil.
Germicidal radiation sources 24 and 26 preferably comprise a plurality of ultraviolet lamps 28 such that total failure of either radiation source by failure of all of the lamps is most unlikely. Lamps 28 are preferably tube shaped and pipe 22 is preferably mounted on telescoping, modular inner, middle and outer sections 30, 32 and 34 for simplicity of manufacture and maintenance as more particularly described hereinafter.
As best seen in FIG. 7, inner section 30 includes a pair of circular end plates 36 joined by nut 38 to a hollow rod 40, the opposite ends of which are threaded. Lamps 28 making up germicidal radiation source 24 are mounted in supporting sockets 42 between circular end plates 36. Four lamps are shown in the particular embodiment illustrated, symmetrically disposed between said plates about the surface thereof. With continuing reference to FIG. 7, a circular electrical mounting plate 44 having the same diameter as end plates 36 and bearing electrical connector 46 is mounted on rods 48 to left plate 36. The electrical leads for sockets 42 on right hand plate 36, which for the purpose of clarity are not shown in the drawings, are threaded through hollow rod 40 and dressed with leads from sockets 42 on left hand plate 36, also not shown, for connection to electrical connector 46.
The details of outer section 34 are shown in FIG. 5 and are similar to those of inner section 30 but differ in the following respects. Outer section 34 includes a pair of annular end plates 50 within which inner and middle sections 30 and 32 are telescoped. Annular end plates 50 are bound together by nuts 38 to four hollow rods 40 which are symmetrically arranged around each end plate 50. Six lamps 28 make up germidical radiation source 26 and are mounted in pairs about the inner surface of annular end plates 50 between adjacent rods 40 in supporting sockets 42. An annular electrical plate 52 having the same configuration as end plates 50 and bearing an electrical connector 46 is mounted on three rods 48 to left plate 50 as viewed in FIG. 5. The electrical leads (not shown) from sockets 42 on right plate 50 are threaded through hollow rods 40, and dressed with leads (not shown) from sockets 42 on left hand plate 50 for connection to electrical connector 46.
Middle section 32 fits between inner and outer sections 30 and 34. Referring to FIG. 6 taken in connection with FIGS. 3 and 4, it is seen that middle section 32 includes a pair of annular end plates 54 which when assembled as shown in FIGS. 3 and 4, concentrically receive circular end plates 36 and are in turn received within annular end plates 50. End plates 54 are bound together by nuts 38 to four solid rods 41 which are symmetrically arranged around each end plate 54. In addition to joining end plates 54, rods 41 form a support for maintaining the diameter of helical coil of pipe 22. As best seen in FIG. 6, a first port 56 is provided in right hand end plate 54 and a second port 58 is provided in left hand end plate 54 through which fluid media is flowed. Ports 56 and 58 are preferably arranged such that they come from the same side of the helix into which pipe 22 is coiled.
Inner, middle and outer sections 30, 32 and 34 are housed within cylindrical casing 60 which is sized to receive the assembled sections. A pair of bulkheads 62 and 64 are provided in casing 60 to align the sections during assembly and hold them during use. As shown in FIG. 2, the bulkhead at the right hand end of sections 30, 32 and 34 comprises a circular plate 68 which is fixed in casing 60 and which has a plurality of upstanding indexing pins 70 that are received during assembly of the unit in correspondingly aligned holes 72 in sections 30, 32 and 34 provided in end plates 36, 54 and 50, respectively. An end cap 74 completes the assembly at the right end of casing 60. A hole 75 is provided through end cap 74 and bulkhead 62 for connecting a pipe to port 56.
In addition to upstanding indexing pins 70, bulkhead 64 has mating electrical connectors 76 for attachment to the electrical connectors 46 carried by electrical mounting plates 44 and 52 such that when the indexing pins are received in correspondingly aligned holes 72 in sections 30, 32 and 34 located in end plates 36, 54 and 50, respectively, the electrical connectors on the bulkhead are mated with the electrical connectors on the electrical mounting plates. The electrical leads 77 from the mated connectors pass through bulkhead 64 and terminate in another electrical connector 78, a mate 80 to which is carried by end cap 82 located at the left end of casing 60 such that when the end cap is removed, the electrical circuit is broken. The electrical leads from connector 80 pass through the end cap and are routed to different ballasts (not shown) which are externally housed so that they will not be wetted if there is a leak in the system. Different ballasts are provided so that if one ballast fails, not all of the lamps on either the inner or outer section will fail. Hole 75 is provided through end cap 82 and bulkhead 64 for connecting a pipe to port 58.
The physical conformation and chemical nature of pipe 22 are very important for the purpose of accomplishing the objects of the present invention. To maximize the exposure of the fluid media to the germicidal radiation source, pipe 22 is preferably a thin walled, corrugated tube wound in a tight helix around radiation source 24 and formed of a tough, flexible fluorinated polyalkylene resin which is resistant to the buildup of film on the inner surface thereof and which remains transparent to ultraviolet rays over an extended period of time. Suitable tubing satisfying all of the above-mentioned criteria are described in the following Military Specification Sheets, which are incorporated by reference herein: MIL-T-81914/6(AS), dated July 14, 1976, for ethylene-tetrafluoroethylene and in MIL-T-81914/4(AS), dated Feb. 28, 1973 for fluorinated ethylene propylene. While either ethylene-tetrafluoroethylene or fluorinated ethylene propylene can be used, the performance characteristics of ethylene-tetrafluoroethylene are superior in all respects.
For use in the present invention, pipe 22 must be sufficiently tough to withstand the pressure of the fluid being flowed through the sterilizer unit but, on the other hand, thin walled enough not to interfere with the transmissibility of the ultraviolet light. When the pipe 22 is formed of ethylene-tetrafluoroethylene or fluorinated ethylene propylene, tubing having a wall thickness as set forth in the above mentioned specifications may be used. The diameter of pipe 22 is also critical since germicidal efficiency is dependent not only on the thickness of the walls but also on the transmissibility of the fluid being treated and on the output of lamps 28. When unit 20 is as shown in the drawings and when each lamp 28 is in the range of 15 to 65 watts, pipe 22 should not be larger than about 1.5 inches in diameter. While a smaller pipe can be used and favors a better kill, it reduces the volume of fluid being sterilized and limits the volumetric flow from the sterilizer unit. A larger pipe favors volumetric flow but compromises the bacterial reduction. Longer residence times of the fluid media in the presence of the germicidal radiation source increase the kill rate. Since the length of lamps 28 generally correlates with the wattage and the length of pipe 22 which can be wound around lamps 28 depends of the length of the lamps, the residence time of the fluid media can be regulated by the selection of the lamps to that amount which is sufficient to reduce the bacterial count to an acceptable level.
In addition to being tough, pipe 22 must be flexible such that it can be bent into a tight helix around lamps 28. For this purpose, pipe which is useful in the present invention has a minimum bend radius of at least 4 inches. Many grades of fluorinated ethylene propylene or the like are unsuitable for use in the present invention because they lack the required degree of flexibility. As shown in FIGS. 1, 2 and 6, pipe 22 is wound with adjacent coils of pipe touching each other around a radius which is slightly larger than that of inner section 30, preferably no more than about 1/4 inch larger. While pipe 22 can be coiled less tightly depending on the bacterial kill required, the configuration described above is preferred because it increases the germicidal efficiency of the unit by maximizing the intensity of the light received by the pipe 22 and the available energy absorbed by the fluid being sterilized. Pipe 22 is also corrugated with internal grooves 84 which are generally transverse to the flow of fluid through the pipe. Grooves 84 are preferably helical as shown in FIGS. 8 and 9 or annular as shown in FIGS. 10 and 11. Grooves 84 function to churn the media as it flows through the pipe so that all of the media comes into close proximity to the walls of the tube for a more homogeneous kill.
In the embodiment illustrated in the drawings, there are no joints or seams in pipe 22 between ports 56 and 58 thus eliminating the potential for leakage. In use, fluid media is passed through pipe 22 between ports 56 and 58 while the media is simultaneously exposed to ultraviolet germicidal radiation from radiation sources 24 and 26 along the entire length of the pipe. As the fluid media flows through pipe 22, grooves 84 churn the media so that all of it comes in close proximity to the walls of the pipe for a more homogeneous kill. The flow rate through pipe 22 and distance traveled are adjusted such that the desired reduction in bacterial count occur.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions and methods without departing from the scope of the invention it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2935611 *||26 Jul 1957||3 May 1960||Corn Products Co||Ultra-violet sterilization apparatus|
|US3550782 *||9 May 1968||29 Dec 1970||Louis P Veloz||Water sterilizer apparatus|
|US3566105 *||16 Aug 1968||23 Feb 1971||Ultra Dynamics Corp||System for ultraviolet irradiation of fluids with fail safe monitoring means|
|US3700406 *||12 Mar 1971||24 Oct 1972||Landry Alfred||Sterilizer unit for fluid media|
|US3894236 *||10 Dec 1973||8 Jul 1975||Hazelrigg Wayne K||Device for irradiating fluids|
|US4400270 *||9 Nov 1981||23 Aug 1983||Adco Aerospace, Inc.||Ultraviolet apparatus for disinfection and sterilization of fluids|
|CA674555A *||19 Nov 1963||Allsafe Water Sterilizer Ltd||Ultra violet sterilization apparatus|
|DE881096C *||9 Oct 1942||25 Jun 1953||Siemens Ag||Einrichtung zur Ultraviolettbestrahlung von Fluessigkeiten|
|DE910777C *||5 Dec 1950||6 May 1954||Siemens Ag||Ultraviolett-Bestrahlungsgeraet fuer Gase, Daempfe und Fluessigkeiten|
|GB707575A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4948980 *||20 Jul 1989||14 Aug 1990||Wedeco Gesellschaft Fur Entkeimungsanlagen M.B.H.||Apparatus for irradiating media with UV-light|
|US4968437 *||19 Apr 1988||6 Nov 1990||Electrolux Water Systems, Inc.||Fluid purification system|
|US4968891 *||22 Nov 1989||6 Nov 1990||Jhawar Makhan M||Disinfecting a fluid with ultraviolet radiation|
|US5068030 *||9 Nov 1990||26 Nov 1991||Oxford Science Industrial Co., Ltd.||Water filtering sterilizing and heating apparatus|
|US5069782 *||26 Apr 1990||3 Dec 1991||Electrolux Water Systems, Inc.||Fluid purification systems|
|US5069885 *||23 Apr 1990||3 Dec 1991||Ritchie David G||Photocatalytic fluid purification apparatus having helical nontransparent substrate|
|US5120450 *||27 Dec 1989||9 Jun 1992||Stanley Jr E Glynn||Ultraviolet radiation/oxidant fluid decontamination apparatus|
|US5133932 *||28 Mar 1989||28 Jul 1992||Iatros Limited||Blood processing apparatus|
|US5141636 *||8 Jan 1991||25 Aug 1992||United States Of America As Represented By The Administrator, National Aeronautics And Space Administration||Purification system|
|US5144146 *||11 Apr 1991||1 Sep 1992||Ultraviolet Energy Generators, Inc.||Method for destruction of toxic substances with ultraviolet radiation|
|US5150705 *||12 Jul 1989||29 Sep 1992||Stinson Randy L||Apparatus and method for irradiating cells|
|US5247178 *||12 Dec 1991||21 Sep 1993||Fusion Systems Corporation||Method and apparatus for treating fluids by focusing reflected light on a thin fluid layer|
|US5320749 *||26 Mar 1992||14 Jun 1994||Mullen Patrick J||Apparatus for treatment of fluid media with ultraviolet irradiation|
|US5352357 *||18 Feb 1993||4 Oct 1994||Perry Cliff R||Waste water treatment system|
|US5366705 *||8 Jun 1993||22 Nov 1994||James J. Reidy||Gravity feed ultraviolet liquid sterilization system|
|US5376281 *||21 Jul 1993||27 Dec 1994||Safta; Eugen||Water purification system|
|US5413768 *||8 Jun 1993||9 May 1995||Stanley, Jr.; E. Glynn||Fluid decontamination apparatus having protected window|
|US5422488 *||17 Sep 1993||6 Jun 1995||Heraeus Holding Gmbh||Reactor apparatus|
|US5433738 *||25 Jan 1994||18 Jul 1995||Stinson; Randy L.||Method for irradiating cells|
|US5536395 *||22 Mar 1993||16 Jul 1996||Amway Corporation||Home water purification system with automatic disconnecting of radiant energy source|
|US5562822 *||15 Mar 1995||8 Oct 1996||Sun River Innovations, Ltd.||Apparatus for removing contaminants from waste fluids|
|US5698091 *||18 Sep 1996||16 Dec 1997||Amway Corporation||Home water purification system with filter end of life monitor|
|US5785845 *||9 Nov 1995||28 Jul 1998||Colaiano; Robert||Water purifying system|
|US5792433 *||8 Mar 1996||11 Aug 1998||Photoscience Japan Corporation||Light irradiating device with easily replaceable light irradiating lamps|
|US5853572 *||25 Jan 1997||29 Dec 1998||Amway Corporation||Home water purification system|
|US5861123 *||26 Apr 1996||19 Jan 1999||Ceco Filters, Inc.||Ultraviolet light irradiated ebullating mass transfer system|
|US5874741 *||3 Mar 1997||23 Feb 1999||Matschke; Arthur L.||Apparatus for germicidal cleansing of water|
|US5997812 *||1 Aug 1996||7 Dec 1999||Coolant Treatment Systems, L.L.C.||Methods and apparatus for the application of combined fields to disinfect fluids|
|US6083387 *||20 Jun 1996||4 Jul 2000||Burnham Technologies Ltd.||Apparatus for the disinfection of fluids|
|US6228327||7 Feb 2000||8 May 2001||Molecucare, Inc.||Apparatus and method for simultaneously germicidally cleansing air and water|
|US6784440||26 Jul 2002||31 Aug 2004||Boc, Inc.||Food sanitizing cabinet|
|US6916452 *||12 Oct 2000||12 Jul 2005||Hydrozone, Ltd.||Sterilization of liquids using ultra-violet light|
|US6932903 *||11 Jun 2003||23 Aug 2005||Senno Technology Inc.||Ultraviolet-and-ozone disinfection apparatus having improvement on disinfection effect|
|US7160566||7 Feb 2003||9 Jan 2007||Boc, Inc.||Food surface sanitation tunnel|
|US8067749 *||8 Feb 2007||29 Nov 2011||Bayer Technology Services Gmbh||Cleanable helical modules|
|US8127667||27 Mar 2009||6 Mar 2012||Gea Farm Technologies, Inc.||Apparatus for pasteurizing milk for feeding to calves|
|US8448569||1 Mar 2012||28 May 2013||Gea Farm Technologies, Inc.||Apparatus for treating milk|
|US8591730||28 Jul 2010||26 Nov 2013||Siemens Pte. Ltd.||Baffle plates for an ultraviolet reactor|
|US8652336||5 Jun 2007||18 Feb 2014||Siemens Water Technologies Llc||Ultraviolet light activated oxidation process for the reduction of organic carbon in semiconductor process water|
|US8741155||17 Jan 2011||3 Jun 2014||Evoqua Water Technologies Llc||Method and system for providing ultrapure water|
|US8753522||17 Jan 2011||17 Jun 2014||Evoqua Water Technologies Llc||System for controlling introduction of a reducing agent to a liquid stream|
|US8758630||26 Jan 2011||24 Jun 2014||Britenstine Incorporated||Waste water processing system and method|
|US8877067||25 May 2012||4 Nov 2014||Evoqua Water Technologies Llc||Method and arrangement for a water treatment|
|US8961798||17 Jan 2011||24 Feb 2015||Evoqua Water Technologies Llc||Method for measuring a concentration of a compound in a liquid stream|
|US20040140269 *||11 Jun 2003||22 Jul 2004||Chang Steven Shih-Yi||Ultraviolet-and-ozone disinfection apparatus having improvement on disinfection effect|
|US20050035301 *||8 Oct 2003||17 Feb 2005||Xiaoling Wang||Apparatus and a method for improving sanitation effectiveness of UV light|
|US20140186500 *||23 Dec 2013||3 Jul 2014||The Regents Of The University Of California||Devices and methods for reducing the microbial load on an object using a uv light source|
|DE4000369A1 *||9 Jan 1990||11 Jul 1991||Layer & Knoedler Abwassertechn||Verfahren und vorrichtung zur abwasserbehandlung|
|EP0378716A1 *||16 Jan 1989||25 Jul 1990||Robert E. Tucker||Sterilizer unit for fluid media and process|
|EP0430581A2 *||22 Nov 1990||5 Jun 1991||Makhan M. Jhawar||Fluid irradiation|
|EP0508338A1 *||4 Apr 1992||14 Oct 1992||Ultra Systems Gmbh Uv-Oxidation||Method and device for degrading organic contaminants by means of photolysis|
|WO1997048421A2 *||20 Jun 1997||24 Dec 1997||Burnham Technologies Ltd||Apparatus and methods for the disinfection of fluids|
|WO2003105926A1 *||16 Jun 2003||24 Dec 2003||Karp Nelson M||Treatment of blood with light|
|WO2010055288A1 *||10 Nov 2009||20 May 2010||Statiflo International Limited||Uv irradiation apparatus and method|
|WO2011162877A1 *||10 May 2011||29 Dec 2011||Siemens Pte. Ltd.||Ultraviolet reactor baffle design for advanced oxidation process and ultraviolet disinfection|
|WO2012044264A1 *||27 Sep 2010||5 Apr 2012||Koepruelue Yusuf Kemal||Method for the cold sterilization and pasteurization of opaque, translucent or transparent liquids|
|U.S. Classification||422/24, 422/198, 250/438, 250/504.00R, 250/437, 210/748.11|
|International Classification||C02F1/32, A61L2/10|
|Cooperative Classification||A61L2/10, C02F1/325|
|European Classification||C02F1/32D, A61L2/10|
|11 Feb 1991||AS||Assignment|
Owner name: BANK OF ST. ELIZABETH,, MISSOURI
Free format text: SECURITY INTEREST;ASSIGNOR:TUCKER, ROBERT;REEL/FRAME:005594/0886
Effective date: 19910130
|18 Feb 1992||FPAY||Fee payment|
Year of fee payment: 4
|27 Aug 1996||REMI||Maintenance fee reminder mailed|
|26 Dec 1996||FPAY||Fee payment|
Year of fee payment: 8
|26 Dec 1996||SULP||Surcharge for late payment|
|23 Mar 1999||AS||Assignment|
Owner name: BANK OF ST. ELIZABETH, MISSOURI
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TUCKER, ROBERT E.;REEL/FRAME:009833/0358
Effective date: 19990313
|4 Apr 2000||FPAY||Fee payment|
Year of fee payment: 12